Across and To

Across adverb - From one side to the other of an intervening space.

To and across are semantically related in on topic. In some cases you can use "To" instead a preposition "Across", when it comes to topics like via, upon.

To preposition - Earlier than.

Across and to are semantically related in on topic. Sometimes you can use "Across" instead a preposition "To", if it concerns topics such as via, upon.